The use of fluoride ion in the dental industry to treat teeth for the prevention and/or inhibition of dental decay is well known. Until recent years, primarily inorganic fluoride salts, such as sodium fluoride, have been utilized as the fluoride ion source not only in rinses, toothpastes and fluorides treatments, but also in dental composites, sealants, adhesives and the like. In regard to these latter materials, the inorganic fluoride salt is suspended in any suitable monomeric or polymeric system and fluoride ion release is accomplished by a diffusion/dissolution mechanism. Such suspensions are difficult to maintain, i.e., the inorganic salt tends to settle and/or separate, and often require repeated mixing or shaking by the user to ensure a homogeneous blend. The subsequent dissolution of a particle of salt in the polymerized article is also a concern, since this may compromise the performance of the composite.
U.S. Pat. No.3,341,505 discloses a film-forming composition which is the polymerization product of an acrylate or methacrylate-functional amine-containing monomer, which is typically reacted with an appropriate acid to form a halide, sulfate or sulfonate salt, and acrylates or methacrylates of alkyl alcohols containing 1 to 12 carbon atoms. These compositions are used as flexible water-soluble films on the skin or as cement compositions for adhering bandages to the skin.
U.S. Pat. No. 4,515,910 discloses a fluoride-releasing interpolymer which is the reaction product of a monomer bearing an anion-exchange site carrying fluoride ions (for example, a quaternary ammonium fluoride), a copolymerizable alkyl acrylate or methacrylate monomer of about 12 carbon atoms and a crosslinking monomer. This composition is disclosed as having utility as a sealant or restorative dental material, as a removable oral device for delivering fluoride and as a bone cement in bio-medical applications.
There is disclosed in International Application PCT/US82/00695 a dental composition comprising a controlled-release fluoride source which comprises a complex of a fluoride-containing Lewis acid and a Lewis base. The preferred Lewis acid is BF.sub.3 and the Lewis base portion of the complex may be, inter alia, an amine capable of free radical polymerization with the other prepolymeric material of the composition.
M. Tanaka, et al, J. Dent. Res. 1987, 66, 1591, describes a fluoride-releasing methacryloyl fluoride-methyl methacrylate copolymer used as a dental sealant.